I have been using a Microsoft 365 family subscription for years and Onedrive to store files and for backup. Almost two years ago I switched to Mac (and I am extremely happy) and purchased Apple One premium for the family.
What I would like to do is to “mirror” the two cloud drives so to end up having two exact copies of my files and backups.
I have tried to simply drag and drop files from finder and it works, but it’s a manual process.
Now I would like to automate this process . I have tried using some classical tools as pathfinder, commander one or forklift but they won’t work, I guess because they can’t directly mount iCloud (but they can mount Onedrive).
Is there a tool out there I can use to keep the two drives in sync automatically?
Thank you
Are you wanting to do it “backup” style - at some interval all the information on one service is copied to the other for retention purposes?
Or “sync” style - when adding or editing files you’re just as likely to open it from one cloud service as the other.
I can see “sync” style having a fair number of reliability issues in addition to being more complicated to set up.
You could use rsync run on a periodic schedule to do this and it comes with MacOS by default. I don’t recall if the preferred way of scheduling tasks Macs is cron, but it’s included too. I’m also not sure if you’d run into file permission issues but I would hope not.
If you’re not comfortable getting into Unix-y things then there are GUI front ends for this, including Carbon Copy Cloner and SuperDuper. They include both sync and scheduling in a single app and are generally more “friendly” than the command line tools that they leverage.
I’d be careful doing this though, and if you choose to do it then I’d consider doing it only in one direction, with one of the services being your working directory and the other being used purely for backup. It’s really, really easy to end up with a nightmare of files having been modifed in both places and then having to work out which changes you want to keep and which you want to discard.
If it’s backup that you’re looking for, I’d consider something that’s meant for backups, like Backblaze, but that’s just an unsolicited bit of advice that you should feel free to disregard 
I agree with @ACautionaryTale
I’ve used ChronoSync for years and used/tested it with Google Drive and OneDrive. It has a 15 day free trial.
this, This, THIS!!!
Two way sync can quickly become a mess unless you are using a service built to do it. You need to have one version which is the source (I.e. the truth) and one which is a mirror of the other.
If you’re going cloud anyway, I’d recommend BackBlaze as it keep 12 months of versions and they have been faultless for me. I’ve twice restored significant amounts of data from BackBlaze and it saved my bacon.
I would like to thank everybody for your answers.
Yes, Backblaze would be great but it would be another cloud service to pay for.
I already pay 90€ for Microsoft 365 every year and 35€/month for apple one premium, Blackblaze would be another 100$ which I can hardly justify.
I am familiar with rsync (I am a unix sysadmin, mainly on Solaris) but I would prefer to have a graphical tool and avoid other work 
I am testing Chronosync on a Onedrive folder (source) with a single direction folder on iCloud, let’s see the outcome, it’s about 8,7 Gb, I guess it’s a valid test. I will update this conversation for future reference.
Thank you again
Update: it finished with no error in less than 1 hour (on a 1Gb FTTH).
Files on iCloud are online only (download removed)… I would say it works great
I think I will manually sync the folders (I mean, have the same files on both cloud drives) and then let Chronosync keep them sync’d after changes, which I expect to seldom happen as they all are sort of backup/archive folders.
Sorry to hijack your thread but…
This is too high what Apple is charging!!
For reference in India, I pay Rs 365/month for family plan (Approx 3.99 Euro/month)
this is from Apples website
Granted there is no Apple News in India, but the price difference (almost 8.75 times) is staggering 
MultCloud can do that:
Many companies offer different pricing in different countries based on macro and microeconomic reasons.
I suggest if you want to do a reasonable comparison, normalizing monthly pricing based on percentage of average monthly consumer income might be a good starting point.
100% this!
One direction only unless you love pain!
My Apple one premium plan has 2 Tb storage for all users and fitness plus (honestly I don’t use it), maybe that can explain the difference, at least partly. No Apple News here too, unfortunately.
In Europe prices are about the same, I think it is related to the average income.
Aah I think it’s the storage.
Its funny in India since software service charge is lower but the Apple hardware is always way too expensive